so with NXT, if i have a wallet with say 1000 NXT, how long does it take to 'forge' new coins and how much will i get in return?

is there a minimum of coins you have to hold?

can someone give me a quick summary please?  if you dont 'mine' nxt but rather earn them just by running a wallet then i'll give it a go.  I've never really read much into the whole proof of stake thing.